"Officially in cheesy dad mode," the "Sing-Off" host, 38, confessed. "Camden is easily the most amazing thing that has happened in my life. Vanessa Lachey and I are truly blessed!"

"We are incredibly proud to announce the birth of our beautiful baby boy, Camden John Lachey," the Lacheys, who wed in July 2011, told Us Weekly in a statement early Thursday. "Born today at 6:54 pm. He came into this world at 8lbs 9oz and 21 inches. Love has truly been redefined for both of us."

Over the summer, Nick opened up to Us about all the changes he and Vanessa had gone through in the past year. "You get married, you get pregnant, and it all kind of happened so fast," he said. "But it's very exciting!"